With this proposal, we request support for the 9th, 10th and 11th conferences on cell Proliferation. The 9th conference which is scheduled to be held from August 24 - August 30th, 1981 will cover "Hormone-dependent Growth and Defined Media". The projected subject for the 10 conference in the summer of 1982 is "Hormone Receptors", and for the 11th conference in the summer of 1983, "Cell-substratum Interactions". As in the past, all of the papers of the invited speakers will be published as a volume of the Cold Spring Harbor Conferences on Cell Proliferation.